In a computer aided design (CAD) interface, drafting applications provide a user an ability to draw and annotate an angle. The angle is a figure formed by two non-parallel lines or line segments where the two lines ultimately extend so that the two lines intersect at a point creating a vertex. The angular dimension is an annotation of the angle comprising of two extension lines and an arc located some distance from the vertex of the angle sweeping the annotated angle. In addition, a textual display of the size of the angular dimension is typically displayed in the CAD interface with the annotated angle.
Many CAD applications are limited to creating annotated angles between explicit line geometry drafted in the CAD interface. These CAD applications require the user to draw two explicit lines or two explicit objects comprised of two lines in the CAD interface. If the user draws the two explicit lines so the two explicit lines intersect, then the intersection of the two explicit lines forms the vertex creating the angle. The CAD interface can then annotate the angle with the angular dimension. If the user simply draws two explicit lines that do not explicitly intersect on the CAD interface, the user must then define an exact center point to be the vertex of the angle. With the two lines drawn by the user and the exact designation of the vertex of the angle, the CAD application can create the angle and annotate the angle with the angular dimension between the two explicit lines with the user defined vertex.